plus addressing improvements

* first `+` splits local part from sub-address
* prioritize plus addressing over domain wildcards

1 files changed, 13 insertions, 10 deletions

diff --git a/realrcptto.c b/realrcptto.c
index 93a7aad..0f275ba 100644
--- a/realrcptto.c
+++ b/realrcptto.c
@@ -173,17 +173,20 @@ static char *virtualext(stralloc *localpart, unsigned int at)
   unsigned int i;
   char *x;
 
-  for (i = at; i > 0; --i)
-    if (localpart->s[i] == '+' /*|| localpart->s[i] == '-'*/) break;
-  if (i == 0 || i == at - 1) return NULL;
-
-  if (!stralloc_copyb(&newaddr, localpart->s, i)) die_nomem();
-  if (!stralloc_catb(&newaddr, localpart->s + at, localpart->len - at)) die_nomem();
-  x = constmap(&mapvdoms, newaddr.s, newaddr.len);
-  if (!x) return NULL;
+  /* sub-addressing: ignore first and last character in local part */
+  for (i = 1; i < at - 1; ++i) {
+    if (localpart->s[i] == '+' /*|| localpart->s[i] == '-'*/) {
+      if (!stralloc_copyb(&newaddr, localpart->s, i)) die_nomem();
+      if (!stralloc_catb(&newaddr, localpart->s + at, localpart->len - at)) die_nomem();
+      x = constmap(&mapvdoms, newaddr.s, newaddr.len);
+      if (!x) return NULL;
+
+      localpart->s[i] = '-';
+      return x;
+    }
+  }
 
-  localpart->s[i] = '-';
-  return x;
+  return NULL;
 }
 
 // max lookups